photosynthesis notes - Biology Junction

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Leaf carbon isotope composition (δ13C) has been used to screen for water-use efficiency in C3 plants, but gaps in the understanding of factors influencing δ13C have limited its application in C4 species. This study exploited maize genetic diversity to explore biochemical and post-photosynthetic factors that may influence δ13C. Our findings indicate that the observed variation in leaf carbon isotope composition across diverse maize lines is likely driven by differences in stomatal and mesophyll conductance and not photosynthetic or respiratory metabolism.

20/01/2010 · CIÊNCIAS FLORESTAIS

They found that elevated CO2 increased rates of net photosynthesis in about 85% of the reported studies, while reducing stomatal conductances and rates of transpiration in approximately 75% of the cases analyzed....

While oxygen is necessary for the process of respiration, glucose plays a crucial role in the diet; and that explains why the photosynthesis is important for all the lifeforms on the planet - including humans.

Transpiration is the loss of water from a plant in the form of water vapor. Water is absorbed by roots from the soil and transported as a liquid to the leaves via xylem. In the leaves, small pores allow water to escape as a vapor and CO2 to enter the leaf for photosynthesis. Of all the water absorbed by plants, less than 5% remains in the plant for growth and storage following growth. This lesson will explain why plants lose so much water, the path water takes through plants, how plants might control for too much water loss to avoid stress conditions, and how the environment plays a role in water loss from plants.

On each side of the stoma there is a guard cell with chloroplasts." title="Internal structure of a leaf" height="380" width="546" style="margin-bottom: 0px;">The internal structure of the leaf is also adapted to promote efficient photosynthesis:

Chlorophyll is the major regulator of photosynthetic antennae in land plants. Its absence diminishes light harvesting, photoprotection and ultimately photosynthesis. We show that barley mutants lacking chl display impaired stomatal control, which can be restored by temporal shading of the plants. Thus the effects of this mutation extend beyond chloroplast metabolism.